linux/Documentation/usb/misc_usbsevseg.txt
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   1USB 7-Segment Numeric Display
   2Manufactured by Delcom Engineering
   3
   4Device Information
   5------------------
   6USB VENDOR_ID   0x0fc5
   7USB PRODUCT_ID  0x1227
   8Both the 6 character and 8 character displays have PRODUCT_ID,
   9and according to Delcom Engineering no queryable information
  10can be obtained from the device to tell them apart.
  11
  12Device Modes
  13------------
  14By default, the driver assumes the display is only 6 characters
  15The mode for 6 characters is:
  16        MSB 0x06; LSB 0x3f
  17For the 8 character display:
  18        MSB 0x08; LSB 0xff
  19The device can accept "text" either in raw, hex, or ascii textmode.
  20raw controls each segment manually,
  21hex expects a value between 0-15 per character,
  22ascii expects a value between '0'-'9' and 'A'-'F'.
  23The default is ascii.
  24
  25Device Operation
  26----------------
  271.      Turn on the device:
  28        echo 1 > /sys/bus/usb/.../powered
  292.      Set the device's mode:
  30        echo $mode_msb > /sys/bus/usb/.../mode_msb
  31        echo $mode_lsb > /sys/bus/usb/.../mode_lsb
  323.      Set the textmode:
  33        echo $textmode > /sys/bus/usb/.../textmode
  344.      set the text (for example):
  35        echo "123ABC" > /sys/bus/usb/.../text (ascii)
  36        echo "A1B2" > /sys/bus/usb/.../text (ascii)
  37        echo -ne "\x01\x02\x03" > /sys/bus/usb/.../text (hex)
  385.      Set the decimal places.
  39        The device has either 6 or 8 decimal points.
  40        to set the nth decimal place calculate 10 ** n
  41        and echo it in to /sys/bus/usb/.../decimals
  42        To set multiple decimals points sum up each power.
  43        For example, to set the 0th and 3rd decimal place
  44        echo 1001 > /sys/bus/usb/.../decimals
  45
  46
  47
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